Yeah the blue really glows on my monitor, I say kick the saturation down a bit and definitely kill the value a little. Same goes for the shadow tones on the trunk, too. As for the amount of leaves to trunk ratio, maybe reduce the size of the trunk? Unless you want to be dealing with a huge canvas size, and most pixellers don't like that

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The shading of the leaves could be worked to reveal more form to the tree, also. As it stands, it looks a little bit flat. I know the reference picture has a similarly flat kind of shading to it, but basing your form on a more spherical shape should make the tree 'pop' more, I reckon.
All over this piece there's a LOT of stray/noisy pixels that seem to fight against the form of the piece. Tone down the texture, boost the shading/forms, up the contrast by dropping the shadows, then once the piece really pops, work the texture in. That is my suggestion.
